1. Technical Field.
The invention relates to a device and a method for checking a fuel rod of a fuel element in a water-filled pool of a nuclear plant.
2. Background and Relevant Art.
During operation of nuclear reactors, individual fuel rods may have defects and develop leaks, as the result of which radioactive fission products may escape into the coolant and increase its radioactivity. This in turn results in an undesirable increase in the radiation exposure in the vicinity of the cooling system. Fuel rods are therefore typically checked for defects every time a fuel rod or fuel element is replaced. For this purpose it is known, for example, to transport the fuel rods, which are not in use and are stored in a water-filled storage pool, in so-called hot cells and inspect them at that location, which is very complex. However, checking in the water-filled pool itself is very difficult, since the measuring devices used are often very sensitive to radiation, and their proper functioning can be ensured only in a water-free environment.
For example, a device for checking a fuel element in a storage pool of a nuclear plant is known from EP 2 208 206 B1, in which the fuel element is checked underwater with a displaceably mounted image detector, such as a camera, and a scale situated in parallel to a longitudinal axis of the fuel element is provided for locating defects in the fuel element.
DE 24 24 431 describes, for example, a device and a method for locating defective fuel rods within a fuel element, in which the fuel element stands in a test container that is stored in a pool of water and covered by a bell, a measuring device being situated in the bell, and the water present in the bell being pressed out by means of a gas stream in order to ensure a water-free space between the measuring device and the fuel rod. However, such a device allows only checking of the upper rod ends or making a distinction between fuel rods that are defective overall and those that are undamaged.